Update.

[bison.git] / src / lalr.c

diff --git a/src/lalr.c b/src/lalr.c
index 275c6ab717a046564c38431f3ad589d5a489d3b3..2c0c942aeb216ab26c958efa11b616a5c0753de3 100644 (file)
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -52,16 +52,6 @@ typedef struct goto_list_s
 } goto_list_t;
 
 
 } goto_list_t;
 
 

-/* LARULE is a vector which records the rules that need lookahead in
-   various states.  The elements of LARULE that apply to state S are
-   those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1.
-
-   If LR is the length of LArule, then a number from 0 to LR-1 can
-   specify both a rule and a state where the rule might be applied.
-   */
-
-static rule_t **LArule = NULL;
-

 /* LA is a LR by NTOKENS matrix of bits.  LA[l, i] is 1 if the rule
    LArule[l] is applicable in the appropriate state when the next
    token is symbol i.  If LA[l, i] and LA[l, j] are both 1 for i != j,
 /* LA is a LR by NTOKENS matrix of bits.  LA[l, i] is 1 if the rule
    LArule[l] is applicable in the appropriate state when the next
    token is symbol i.  If LA[l, i] and LA[l, j] are both 1 for i != j,


@@ -81,29 +71,6 @@ static goto_list_t **lookback;
 
 
 
 
 
 

-static void
-initialize_LA (void)
-{
-  state_number_t i;
-  int j;
-  rule_t **np;
-
-  /* Avoid having to special case 0.  */
-  if (!nLA)
-    nLA = 1;
-
-  LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
-  LArule = XCALLOC (rule_t *, nLA);
-  lookback = XCALLOC (goto_list_t *, nLA);
-
-  np = LArule;
-  for (i = 0; i < nstates; i++)
-    if (!states[i]->consistent)
-      for (j = 0; j < states[i]->reductions->num; j++)
-       *np++ = states[i]->reductions->rules[j];
-}
-
-

 static void
 set_goto_map (void)
 {
 static void
 set_goto_map (void)
 {


@@ -244,21 +211,13 @@ initialize_F (void)
 
 
 static void
 
 
 static void

-add_lookback_edge (state_t *state, rule_number_t ruleno, int gotono)
+add_lookback_edge (state_t *state, rule_t *rule, int gotono)

 {
 {

-  int i;
-  goto_list_t *sp;
-
-  for (i = 0; i < state->nlookaheads; ++i)
-    if (state->lookaheads_rule[i]->number == ruleno)
-      break;
-
-  assert (state->lookaheads_rule[i]->number == ruleno);
-
-  sp = XCALLOC (goto_list_t, 1);
-  sp->next = lookback[(state->lookaheads - LA) + i];
+  int r = state_reduction_find (state, rule);
+  goto_list_t *sp = XCALLOC (goto_list_t, 1);
+  sp->next = lookback[(state->reductions->lookaheads - LA) + r];

   sp->value = gotono;
   sp->value = gotono;

-  lookback[(state->lookaheads - LA) + i] = sp;
+  lookback[(state->reductions->lookaheads - LA) + r] = sp;

 }
 
 
 }
 
 


@@ -276,9 +235,9 @@ build_relations (void)
     {
       int nedges = 0;
       symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;
     {
       int nedges = 0;
       symbol_number_t symbol1 = states[to_state[i]]->accessing_symbol;

-      rule_number_t *rulep;
+      rule_t **rulep;

 
 

-      for (rulep = derives[symbol1]; *rulep >= 0; rulep++)
+      for (rulep = derives[symbol1]; *rulep; rulep++)

        {
          int done;
          int length = 1;
        {
          int done;
          int length = 1;


@@ -286,7 +245,7 @@ build_relations (void)
          state_t *state = states[from_state[i]];
          states1[0] = state->number;
 
          state_t *state = states[from_state[i]];
          states1[0] = state->number;
 

-         for (rp = rules[*rulep].rhs; *rp >= 0; rp++)
+         for (rp = (*rulep)->rhs; *rp >= 0; rp++)

            {
              state = transitions_to (state->transitions,
                                      item_number_as_symbol_number (*rp));
            {
              state = transitions_to (state->transitions,
                                      item_number_as_symbol_number (*rp));


@@ -365,68 +324,72 @@ compute_lookaheads (void)
 }
 
 
 }
 
 

-/*-------------------------------------------------------------.
-| Count the number of lookaheads required for each state       |
-| (NLOOKAHEADS member).  Compute the total number of LA, NLA.  |
-`-------------------------------------------------------------*/
+/*---------------------------------------------------------------.
+| Count the number of lookaheads required for STATE (NLOOKAHEADS |
+| member).                                                       |
+`---------------------------------------------------------------*/

 
 

-static void
-states_lookaheads_count (void)
+static int
+state_lookaheads_count (state_t *state)

 {
 {

-  state_number_t i;
-  nLA = 0;
-
-  /* Count   */
-  for (i = 0; i < nstates; i++)
-    {
-      int k;
-      int nlookaheads = 0;
-      reductions_t *rp = states[i]->reductions;
-      transitions_t *sp = states[i]->transitions;
-
-      /* We need a lookahead either to distinguish different
-        reductions (i.e., there are two or more), or to distinguish a
-        reduction from a shift.  Otherwise, it is straightforward,
-        and the state is `consistent'.  */
-      if (rp->num > 1
-         || (rp->num == 1 && sp->num &&
-             !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0)))
-       nlookaheads += rp->num;
-      else
-       states[i]->consistent = 1;
-
-      for (k = 0; k < sp->num; k++)
-       if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k))
-         {
-           states[i]->consistent = 0;
-           break;
-         }
+  int k;
+  int nlookaheads = 0;
+  reductions_t *rp = state->reductions;
+  transitions_t *sp = state->transitions;
+
+  /* We need a lookahead either to distinguish different
+     reductions (i.e., there are two or more), or to distinguish a
+     reduction from a shift.  Otherwise, it is straightforward,
+     and the state is `consistent'.  */
+  if (rp->num > 1
+      || (rp->num == 1 && sp->num &&
+         !TRANSITION_IS_DISABLED (sp, 0) && TRANSITION_IS_SHIFT (sp, 0)))
+    nlookaheads += rp->num;
+  else
+    state->consistent = 1;
+
+  for (k = 0; k < sp->num; k++)
+    if (!TRANSITION_IS_DISABLED (sp, k) && TRANSITION_IS_ERROR (sp, k))
+      {
+       state->consistent = 0;
+       break;
+      }

 
 

-      states[i]->nlookaheads = nlookaheads;
-      nLA += nlookaheads;
-    }
+  return nlookaheads;

 }
 
 
 }
 
 

-/*--------------------------------------.
-| Initializing the lookaheads members.  |
-`--------------------------------------*/
+/*----------------------------------------------.
+| Compute LA, NLA, and the lookaheads members.  |
+`----------------------------------------------*/

 
 static void
 
 static void

-states_lookaheads_initialize (void)
+initialize_LA (void)

 {
   state_number_t i;
 {
   state_number_t i;

-  bitsetv pLA = LA;
-  rule_t **pLArule = LArule;
+  bitsetv pLA;

 
 

-  /* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
-     state.  */
+  /* Compute the total number of reductions requiring a lookahead.  */
+  nLA = 0;
+  for (i = 0; i < nstates; i++)
+    nLA += state_lookaheads_count (states[i]);
+  /* Avoid having to special case 0.  */
+  if (!nLA)
+    nLA = 1;
+
+  pLA = LA = bitsetv_create (nLA, ntokens, BITSET_FIXED);
+  lookback = XCALLOC (goto_list_t *, nLA);
+
+  /* Initialize the members LOOKAHEADS for each state which reductions
+     require lookaheads.  */

   for (i = 0; i < nstates; i++)
     {
   for (i = 0; i < nstates; i++)
     {

-      states[i]->lookaheads = pLA;
-      states[i]->lookaheads_rule = pLArule;
-      pLA += states[i]->nlookaheads;
-      pLArule += states[i]->nlookaheads;
+      int count = state_lookaheads_count (states[i]);
+      if (count)
+       {
+         states[i]->reductions->lookaheads = pLA;
+         pLA += count;
+       }

     }
 }
 
     }
 }
 


@@ -443,18 +406,26 @@ lookaheads_print (FILE *out)
   fprintf (out, "Lookaheads: BEGIN\n");
   for (i = 0; i < nstates; ++i)
     {
   fprintf (out, "Lookaheads: BEGIN\n");
   for (i = 0; i < nstates; ++i)
     {

+      reductions_t *reds = states[i]->reductions;

       bitset_iterator iter;
       bitset_iterator iter;

+      int nlookaheads = 0;
+
+      if (reds->lookaheads)
+       for (k = 0; k < reds->num; ++k)
+         if (reds->lookaheads[k])
+           ++nlookaheads;

 
       fprintf (out, "State %d: %d lookaheads\n",
 
       fprintf (out, "State %d: %d lookaheads\n",

-              i, states[i]->nlookaheads);
+              i, nlookaheads);

 
 

-      for (j = 0; j < states[i]->nlookaheads; ++j)
-       BITSET_FOR_EACH (iter, states[i]->lookaheads[j], k, 0)
-       {
-         fprintf (out, "   on %d (%s) -> rule %d\n",
-                  k, symbols[k]->tag,
-                  states[i]->lookaheads_rule[j]->number);
-       };
+      if (reds->lookaheads)
+       for (j = 0; j < reds->num; ++j)
+         BITSET_FOR_EACH (iter, reds->lookaheads[j], k, 0)
+         {
+           fprintf (out, "   on %d (%s) -> rule %d\n",
+                    k, symbols[k]->tag,
+                    reds->rules[j]->number);
+         };

     }
   fprintf (out, "Lookaheads: END\n");
 }
     }
   fprintf (out, "Lookaheads: END\n");
 }


@@ -462,9 +433,7 @@ lookaheads_print (FILE *out)
 void
 lalr (void)
 {
 void
 lalr (void)
 {

-  states_lookaheads_count ();

   initialize_LA ();
   initialize_LA ();

-  states_lookaheads_initialize ();

   set_goto_map ();
   initialize_F ();
   build_relations ();
   set_goto_map ();
   initialize_F ();
   build_relations ();


@@ -481,10 +450,6 @@ lalr_free (void)
 {
   state_number_t s;
   for (s = 0; s < nstates; ++s)
 {
   state_number_t s;
   for (s = 0; s < nstates; ++s)

-    {
-      states[s]->lookaheads = NULL;
-      states[s]->lookaheads_rule = NULL;
-    }
+    states[s]->reductions->lookaheads = NULL;

   bitsetv_free (LA);
   bitsetv_free (LA);

-  free (LArule);

 }
 }